Browsing by Author "Takeda, Nobuo"

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    Development of Portable Gas Chromatograph Using Ball Surface Acoustic Wave Sensor for Measurement of Crewed Space Environment
    (51st International Conference on Environmental Systems, 7/10/2022) Iwaya, Takamitsu; Akao, Shingo; Yamanaka, Kazushi; Okano, Tatsuhiro; Takeda, Nobuo; Tsukahara, Yusuke; Oizumi, Toru; Fukushi, Hideyuki; Sugawara, Maki; Tsuji, Toshihiro; Tanaka, Tomoki; Takeda, Akinobu; Shima, Asuka; Matsumoto, Satoshi; Sugahara, Haruna; Hoshino, Takeshi; Sakashita, Tetsuya
    A gas chromatograph (GC) is effective as one of the methods for monitoring the atmosphere in a crewed space environment. However, the GC is generally large and difficult to carry. We have developed portable GC systems with a ball surface acoustic wave (SAW) sensor; ball SAW GC. The key features of the ball SAW GC are multiple roundtrips of SAW on a spherical element and a metal micro-electro-mechanical-systems (MEMS) column formed by etching and diffusion bonding of stainless-steel plates. In addition, using the feature of ball SAW sensor that can detect gases non-destructively, we have developed a forward flush method realizing fast analysis of multiple gases by combining two columns and two sensors. In this study, we developed a prototype ball SAW GC applied the forward flush method with the volume of 1 L and which has the same functions as a desktop GC such as a sampler, a preconcentrator, and a column heater. Using this GC, we succeeded in analyzing multiple hazardous gases assumed in the crewed space environment.
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    Development of Portable Gas Chromatograph Using Ball Surface Acoustic Wave Sensor with Air Carrier Gas for Crewed Space Environment Monitoring
    (2024 International Conference on Environmnetal Systems, 2024-07-21) Iwaya, Takamitsu; Akao, Shingo; Takeda, Nobuo; Okano, Tatsuhiro; Fukushi, Hideyuki; Oizumi, Toru; Takeda, Akinobu; Yamanaka, Kazushi; Kaneko, Yosuke; Shima, Asuka
    In a crewed space environment, monitoring of trace volatile compounds in the atmosphere is necessary to ensure the health of the crews and the vehicle systems. Gas chromatographs (GC) are one of the effective tools for analyzing such a wide variety of gases. We have developed a prototype of 1 L sized GC using a ball surface acoustic wave (SAW) sensor, a small and high sensitivity sensor that utilizes multiple roundtrips of the SAW on a spherical element, as the GC's detector. However, the prototype used a hydrogen storage canister to supply the carrier gas, which required strict safety measures for use in space. On the other hand, using supplying nitrogen or helium, which are safe gases, with high-pressure cylinders would increase the weight of the GC system. Therefore, we are studying using recirculated air as a carrier gas without cylinders. However, using air as carrier gas results in lower separation performance than using hydrogen. In this study, we developed a portable GC using the ball SAW sensor with air carrier gas and demonstrated the feasibility of acceptable separation performance.